The shareholders of the Oakland, Calif., company have decided it’s time the company explore a full-on sale — with Liberty Media-backed SiriusXM appearing to be first up at the table, sources told The Post.

“The large shareholders are unified in wanting them to sell. They are going to be forced to start a process either now or in four months,” one shareholder told The Post.

To be sure, not all of Pandora’s board are on the same page — some are not convinced staying a stand-alone company isn’t best, sources said.

The internet radio giant has been diversifying into ticketing and On Demand to decrease its reliance on its core ad-supported internet radio product, and those non-core operation should be given time to flourish, some board members believe, sources said.

Pandora went public at $16 a share back in mid-2011 and shareholders are currently holding out for an offer in the $18 to $20 range, one person told The Post.

The stock closed at $13.33 on Friday, after jumping 16.1 percent on a report that Pandora was open to discussing a sales to SiriusXM.

Despite the report, from CNBC, Sirius is yet to have any conversations at all with Pandora, sources said.

That could change next week.

Liberty Media Chief Executive Greg Maffei said in the summer Sirius XM was interested and had sent a letter of intent to Pandora at $15.

Pandora founder and recently returned CEO Tim Westergren had argued for more time to see if the new On Demand products will bear fruit — but shareholders and large hedge fund owners are singing from the same hymn sheet now.

They want out of their investment.

Centerview Partners and Morgan Stanley have been advising Pandora for months.

There have been some behind-the-scenes talks at Sirius about how an offer at $18.50 would play out, one source familiar with the situation said.

Others close to Sirius deny any new offer has been broached, meaning the early talks have been very informal.

One argument against such a robust offer even being talked about lightly is that Pandora’s business hasn’t improved in the past quarter.

Even so, Pandora is of strategic importance given its huge mobile ad business and experience in streaming media. Sirius might want Pandora to make its audience profile more youthful and take advantage of its demographic ad targeting.

Shareholders want to see if other interested parties will step forward.

Facebook, for instance, has long been looking for an entrance into the music business — and Google has eyed the venture before, a source tells The Post.

Disney may also be interested given that it eyed Twitter and has been feeling out the streaming media world of late.